1. Field of Invention
The present invention relates to the technical field of tunnel engineering, and more particularly to a method for preventing shield jamming due to too large frictional resistance in an earth pressure balance shield machine.
2. Description of Related Arts
During a tunneling process by a shield machine, the occurrence of shield-jamming which causes the inability of forward movement of the cutting disk is not uncommon. When there is changes of formation pressure, the friction between the shield body of the shield machine and the stratum may become too large and lead to the occurrence of shield-jamming. When this kind of construction failure occurs in which the machine is forced to shut down, a very long period of time and a very high cost are required to resolve the problem. For example, auxiliary pilot tunnel is excavated or controlled blasting method is employed to solve the problem, which is labor intensive, time consuming and costly. At present, there is no article about how to prevent the problem of shield jamming due to excessive friction in our nation or abroad.